Pollen season starts about 20 days earlier than in 1990, so plan allergy care sooner

Key takeaways

• Records from 60 North American pollen stations show seasons starting about 20 days earlier in 2018 than in 1990, with about 21% more pollen in the air¹².
• In a 2024 federal survey, 25.2% of U.S. adults reported a diagnosed nasal allergy, a count that includes year-round allergies as well as hay fever⁴.
• Both major U.S. allergy guidelines back steroid nose sprays as a first choice, and a 2020 update strongly advises against older, first-generation antihistamines⁵⁶.
• In May 2025 the FDA warned that rare but severe itching can follow stopping long-term cetirizine or levocetirizine, after finding 209 cases worldwide⁸.
• Saline rinses have modest evidence but need distilled, sterile or boiled water; raw butterbur can harm the liver, and honey hasn’t proven itself¹¹¹².

Across the United States and Canada, small devices on rooftops sample the air so labs can count the pollen in it. Many report to the National Allergy Bureau, a network run by an allergy society³⁷.

In 2021, a team led by William Anderegg of the University of Utah pulled those records from 60 stations, covering 1990 to 2018¹². The pattern was hard to miss. Pollen seasons were starting about 20 days earlier, and the air carried about 21% more pollen over a year¹².

Using climate models, the team linked about half of the shift in season timing to human-caused warming¹.

That matters to a lot of people. In 2024, about 1 in 4 U.S. adults reported a diagnosed nasal allergy⁴.

It also changes the plan. Allergists say allergy medicine works best when you start it before symptoms begin⁷. If your season has moved, your calendar should move with it.

Below: how to track your season, what guidelines put first, two FDA updates and the natural approaches with evidence. Testing and allergy shots get their own companion article on allergic rhinitis.

Your pollen season is longer than the one you grew up with

Trees did most of the damage. Their pollen climbed more than grass or weed pollen, and stations in Texas and the Midwest logged the biggest, steadiest gains². When the team looked for what best explained a station’s rising pollen totals, a warmer average year came out on top².

One detail often gets lost in headlines. Human-caused climate change explained about half of the change in timing, but only about 8% of the rise in pollen amounts¹. The study didn’t pin the rest of the extra pollen on human-caused warming.

The climate signal also grew stronger over time. The researchers put warming’s share of the earlier start at 35% to 66% for 1990 to 2018, and at 45% to 84% for 2003 to 2018 alone².

The study has limits. More stations joined the network in later years, though the authors’ checks found the results held up². It counted pollen, not sneezes, and didn’t measure health effects directly³.

The work was paid for by the Packard Foundation, the National Science Foundation and the U.S. Department of Agriculture, with no industry money listed³.

About 1 in 4 adults has a nasal allergy, and the count depends on the question

The newest national figure comes from the National Center for Health Statistics. Its 2024 household survey found that 25.2% of adults had what it calls a diagnosed seasonal allergy⁴.

The numbers vary across groups⁴:

• Sex. 29.5% of women, compared with 20.7% of men.
• Age. Highest at ages 45 to 64, at 27.7%, and lowest at 75 and older, at 21.7%.
• Race and ethnicity. 28.5% of white adults, 24.4% of Black adults, 17.2% of Asian adults and 16.5% of Hispanic adults.
• Place. 28.1% outside metro areas, compared with 24.8% in them.

Notice how the survey asked. It counted people with sneezing, a runny nose or itchy eyes from hay fever, seasonal allergies or year-round allergies, if a health professional had ever diagnosed them⁴. So the “seasonal” figure also includes some people whose symptoms never take a break.

Other estimates run lower. The ear, nose and throat surgeons’ 2015 guideline said nearly 1 in 6 Americans has allergic rhinitis⁵. The 2020 allergy update put self-reported rates at 10% to 30% of adults, and doctor-confirmed rates at 14%⁶. Much of that gap likely reflects how each study defines a case.

Read the pollen count, then build your season plan

A pollen count is a measurement. A rooftop device collects airborne particles for 24 hours, and a lab identifies them as tree, grass or weed pollen, or mold spores⁷. A forecast is a prediction based on last year’s counts and the current weather⁷.

The National Allergy Bureau posts counts from stations that meet its certification standards⁷. Find the station nearest you and note which pollen type is high.

The American Academy of Allergy, Asthma & Immunology offers two tips. Watch the counts and limit exposure on high days. And start allergy medicine before the season’s first pollen reaches you, since it works best before symptoms develop⁷.

Your own records matter too. Seasons vary by region and, as the Anderegg data show, by decade¹⁷. A note of the dates your symptoms start and stop each year becomes your personal forecast. Our article on symptom diaries explains how to keep one.

Prevention is a core natural-health value, and seasonal allergy rewards it. The best moves come before your nose starts running: know your dates, rinse with safe water and start treatment on time.

The allergy season calendar and plan

Plan by phase, not by month. Your local station and your diary set the dates.

When	What to do	Evidence rating	Source
Right after last season ends	Write down when symptoms started, peaked and faded. If medicines didn’t control them, ask about allergy testing.	Not rated: a guideline step for choosing treatment	5
Before your usual start date (earlier if your seasons have crept)	Start the treatment you and your clinician chose before symptoms begin.	Strong evidence for steroid sprays and newer antihistamines	567
High-count days	Check the count and cut your exposure when your pollen type is high.	Not enough evidence from trials; low cost and low risk	7
Peak weeks	Consider saline rinses with distilled, sterile or boiled-and-cooled water.	Promising but early	1112
Symptoms still bad on one medicine	Ask about pairing a steroid spray with an antihistamine spray.	Strong evidence from high-certainty studies; guidelines call it an option	56
After pollen fades	Don’t be surprised if symptoms linger, since nasal inflammation can outlast the season.	Not rated: guideline discussion	6
If you’ve taken cetirizine daily for months	Know the FDA itching warning, and talk with a clinician about long-term plans.	Not rated: rare, documented harm	8

If your symptoms never fully fade between seasons, the cause may not be pollen at all. That’s the subject of our companion article on allergic rhinitis.

What allergy guidelines put first

The ear, nose and throat surgeons’ 2015 guideline, from the American Academy of Otolaryngology–Head and Neck Surgery, recommends steroid nose sprays when symptoms affect quality of life⁵. For people bothered mainly by sneezing and itching, it recommends newer, second-generation antihistamine pills. It advises against leukotriene pills, such as montelukast, as the main treatment⁵⁶.

The Joint Task Force on Practice Parameters, which represents the two national allergy societies, updated its guidance in 2020⁶. For people 12 and older starting treatment for seasonal allergy, it strongly prefers a steroid spray alone over a spray plus an antihistamine pill⁶.

The 2020 update also names antihistamine nose sprays as a first option. It suggests a steroid-antihistamine spray pairing for moderate to severe symptoms⁶. And it strongly recommends newer antihistamines over older, first-generation ones⁶. Our sleep-aid article explains why geriatric experts advise older adults to avoid first-generation drugs such as diphenhydramine.

Oral decongestants need care. The task force says to use them cautiously in older adults, children under 4 and people with heart, blood vessel, bladder, glaucoma or thyroid problems, and to avoid them in the first trimester of pregnancy⁶.

Two FDA updates to know before you buy

Itching after stopping cetirizine. In May 2025, the FDA announced a new warning for cetirizine (Zyrtec) and levocetirizine (Xyzal)⁸. Some people who stopped after long, daily use developed severe, widespread itching they never had before⁸.

Reports filed between 2017 and 2023 added up to 209 cases around the world, and 197 came from the U.S.⁸. The typical person had been on the drug for 33 months. The itch usually showed up about two days after the last dose, and in 48 cases it was disabling⁸.

For scale, Americans bought about 62.7 million packages of the over-the-counter versions in 2022 alone⁸. The FDA calls the reaction rare, but it has no way to say who will get it⁸.

Going back on the drug brought relief for most: 71 of the 79 people who tried it⁸. No treatment for the itch itself has been studied, the FDA says. If you expect to use either drug for more than a few months, the agency suggests weighing the pros and cons with a clinician first. If severe itching follows stopping, contact one⁸.

Oral phenylephrine. In November 2024, the FDA proposed removing oral phenylephrine from over-the-counter decongestants, because the evidence doesn’t show it works when swallowed⁹. The proposal was about effectiveness, not safety, and it doesn’t affect phenylephrine nose sprays⁹.

A November 2025 news report said the order was still a proposal and that a final decision could come in May 2026¹⁰. As of October 2026, the FDA’s announcement still describes a proposal, and we found no final order⁹. Until there is one, read the active ingredients on the box. Our article on symptom relief tells the story of the FDA advisory panel behind the proposal.

Rinsing works modestly, if the water is safe

Rinsing the nose with salt water is old, cheap and drug-free.

The National Center for Complementary and Integrative Health (NCCIH) cites a 2012 review of 10 studies¹². Regular rinsing for up to seven weeks eased nasal symptoms, cut medicine use and improved quality of life in adults and children with allergic rhinitis¹². The NCCIH calls the benefit modest¹².

The danger is in the water. Tap water can carry small numbers of amoebas. Swallowed, they die in stomach acid. Flushed into the nose, they can live on and cause serious infections, which in rare cases are fatal¹¹.

Improper rinsing may have caused two deaths in Louisiana in 2011, from a rare brain infection that officials tied to amoeba-contaminated tap water¹²¹³.

The FDA’s water rules¹¹:

• Use distilled or sterile water, labeled as such.
• Or boil tap water for 3 to 5 minutes and cool it to lukewarm. Keep it in a clean, closed container and use it within 24 hours.
• Use filtered water only if the filter is made to catch infectious organisms.
• Clean the rinse device every time, and let it dry completely before the next use.

Check with a clinician before rinsing if your immune system isn’t working properly. Call one if symptoms worsen or don’t improve, especially if you get a fever, nosebleeds or headaches while rinsing¹¹. The FDA says to rinse a child’s nose only if a pediatrician recommends it¹¹.

Herbs, honey and acupuncture: what the evidence shows

Butterbur. In six randomized trials with 720 people, pooled in a 2007 review, butterbur (Petasites hybridus) did better than a dummy pill and about as well as non-drowsy antihistamines¹²¹³. There’s a catch. A company that sells butterbur funded three of the bigger trials, and the reviewers stopped short of firm conclusions¹².

Safety is the larger worry. Unprocessed butterbur carries pyrrolizidine alkaloids (PAs), which can injure the liver and may raise cancer risk¹²¹³. Liver concerns have led some countries to take butterbur off the market¹². If you consider it at all, NCCIH’s advice is to look only at products that have had the PAs removed and carry a PA-free label or certification¹².

That label still isn’t a promise. NCCIH notes liver injury in some people taking one brand sold as PA-free¹². In studies lasting up to 16 weeks, PA-free products appeared safe at recommended doses; nobody has shown that longer use is safe¹².

PA-containing products should be avoided in pregnancy and breastfeeding¹². People allergic to ragweed, marigolds or daisies may react to butterbur, too¹². Our article on ragweed-family herbs covers that kind of cross-reaction.

Local honey. Honey can contain small amounts of pollen, and some suggest it might act like an antihistamine or calm inflammation¹³. The best-known test was a 2011 pilot study of 44 people with birch pollen allergy¹². Those who ate birch pollen honey before the season did better than people on usual medicine, and slightly better than those eating regular honey¹².

The authors called those results preliminary, and the NCCIH says there’s no convincing evidence honey eases seasonal allergies¹². Honey isn’t safe for babies under 1, and people with pollen allergy can also react to bee products¹²¹³.

Acupuncture. A 2015 analysis of 13 studies with 2,365 people found acupuncture improved nasal symptoms, medicine use and quality of life¹².

Here the guidelines split. The 2015 ear, nose and throat guideline says clinicians may offer acupuncture to people who want a non-drug option⁵. The 2020 allergy update found the evidence too thin to recommend it either way⁶. With an experienced practitioner and sterile needles, it’s generally considered safe¹³.

Other supplements. Quercetin, spirulina, stinging nettle, grape seed extract, Pycnogenol and others have been studied, but the evidence is inconsistent or too thin to show benefit¹³. For probiotics, NCCIH’s review says the evidence doesn’t support routine use for allergies¹². The 2015 guideline made no recommendation on herbal therapy⁵.

How strong is the evidence?

Approach	Evidence rating	What it rests on
Steroid nose sprays	Strong evidence	First choice in both U.S. guidelines56
Newer (second-generation) antihistamine pills	Strong evidence	Recommended in both guidelines56
Older, first-generation antihistamines	Evidence says no, or unsafe	A strong guideline recommendation favors newer drugs instead6
Oral phenylephrine	Evidence says no, or unsafe	FDA proposed removal because the evidence doesn’t show it works when swallowed9
Saline rinses with safe water	Promising but early	A 2012 review of 10 studies found modest benefits12
Acupuncture	Promising but early	Positive pooled studies; one guideline calls it an option, the other takes no side5612
PA-free butterbur	Promising but early	Six trials, three large ones paid for by a butterbur maker1213
Raw or uncertified butterbur	Evidence says no, or unsafe	Liver-damaging alkaloids1213
Local or birch pollen honey	Not enough evidence	One 44-person pilot study12
Quercetin, spirulina, stinging nettle	Not enough evidence	Inconsistent or limited studies13

When it’s not just seasonal allergies

Get help from a clinician when:

• Treatment isn’t working, or it’s unclear what’s causing your symptoms. The 2015 guideline says that’s when allergy testing is useful⁵.
• You get severe itching after stopping cetirizine or levocetirizine⁸.
• You develop a fever, nosebleeds or headaches while rinsing your nose, or your symptoms get worse¹¹.
• You find yourself reaching for a decongestant nose spray day after day, since longer use can bring rebound congestion¹⁴.
• You’re considering butterbur or another supplement while pregnant, nursing or taking other medicines. The NCCIH advises asking first, since most supplements haven’t been tested in pregnancy or children¹³.

Our companion article on allergic rhinitis covers non-allergic stuffiness, rebound congestion and allergy shots. Later articles in this series cover serious breathing symptoms and finding qualified allergy care.

Questions readers ask

The bottom line

Pollen seasons now start earlier and carry more pollen than they did a generation ago. The smartest move is timing: learn your local counts, track your own dates, and start treatment before symptoms begin.

Steroid nose sprays and newer antihistamines have the strongest evidence. Saline rinses help modestly when the water is safe. Acupuncture and PA-free butterbur have early support, while honey and most supplements remain unproven. If treatment isn’t working, it’s time to find out what you’re really reacting to.

Related reading

• Testing decides what helps a stuffy nose, since not every one is an allergy
• If you’re allergic to ragweed, chamomile, echinacea and feverfew belong to its family
• Plain water gargles cut colds in one trial, while steam bowls have burned children
• How to tell easing a symptom from treating a disease
• The sleep aid with the clearest warning is the drugstore antihistamine

Sources

1. Anderegg WRL, Abatzoglou JT, Anderegg LDL, Bielory L, Kinney PL, Ziska L. “Anthropogenic climate change is worsening North American pollen seasons.” Proceedings of the National Academy of Sciences, 2021;118(7):e2013284118 (repository record and abstract). digitalcommons.kean.edu
2. Tandon A. “Climate change has ‘worsened’ North America’s pollen season.” Carbon Brief, February 8, 2021. carbonbrief.org
3. AJMC. “Longer, More Intense Pollen Seasons Driven by Human-Led Climate Change, Study Says.” American Journal of Managed Care, February 10, 2021. ajmc.com
4. Bottoms-McClain L, Giri A, Ng AE. “Diagnosed Allergic Conditions in Adults: United States, 2024.” NCHS Data Brief No. 545. National Center for Health Statistics, January 2026. cdc.gov
5. American Academy of Otolaryngology–Head and Neck Surgery. “Clinical Practice Guideline: Allergic Rhinitis” (summary of Seidman MD, Gurgel RK, Lin SY, et al., Otolaryngology–Head and Neck Surgery, 2015). AAO-HNS Bulletin, February 6, 2015.
6. Dykewicz MS, Wallace DV, Amrol DJ, et al. “Rhinitis 2020: A practice parameter update.” Journal of Allergy and Clinical Immunology, 2020;146(4):721-767. college.acaai.org
7. American Academy of Allergy, Asthma & Immunology. “Hay Fever and Pollen Counts.” AAAAI Conditions Library, page dated July 16, 2026. aaaai.org
8. U.S. Food and Drug Administration. “FDA requires warning about rare but severe itching after stopping long-term use of oral allergy medicines cetirizine or levocetirizine (Zyrtec, Xyzal, and other trade names).” Drug Safety Communication, May 16, 2025 (content current as of April 3, 2026). fda.gov
9. U.S. Food and Drug Administration. “FDA Proposes Ending Use of Oral Phenylephrine as OTC Monograph Nasal Decongestant Active Ingredient After Extensive Review.” Press announcement, November 7, 2024. fda.gov
10. Foxx R. “‘It just doesn’t work’: FDA proposes to end use of some OTC cold medications.” Spectrum News 1, November 13, 2025. spectrumnews1.com
11. U.S. Food and Drug Administration. “Is Rinsing Your Sinuses With Neti Pots Safe?” Consumer Update, content current as of April 28, 2025. fda.gov
12. National Center for Complementary and Integrative Health. “Seasonal Allergies and Complementary Health Approaches: What the Science Says.” NCCIH Clinical Digest, May 2023. nccih.nih.gov
13. National Center for Complementary and Integrative Health. “Seasonal Allergies at a Glance.” NCCIH, last updated March 2019. nccih.nih.gov
14. Cleveland Clinic. “Oxymetazoline Nasal Spray.” Cleveland Clinic Health Library, accessed October 2026. my.clevelandclinic.org